Conduits for transporting fluids

ABSTRACT

A conduit ( 100 ) for transporting a fluid comprises a first collar ( 102 ), a second collar ( 103 ), a bellows ( 108 ), and a sensor ( 116 ). The bellows ( 108 ) comprises a central axis ( 180 ), a first corrugated outboard ply ( 114 ), a corrugated inboard ply ( 110 ), interposed between the first corrugated outboard ply ( 114 ) and the central axis ( 180 ), an interstitial space ( 126 ), interposed between the corrugated inboard ply ( 110 ) and the first corrugated outboard ply ( 114 ), and a second corrugated outboard ply ( 112 ) within the interstitial space ( 126 ). The corrugated inboard ply ( 110 ), the first corrugated outboard ply ( 114 ), and a weld-through ring ( 150 ) are welded to the first collar ( 102 ) and the second collar ( 102 ). The second corrugated outboard ply ( 112 ) is not hermetically coupled to the first collar ( 102 ) or the second collar ( 103 ). The sensor ( 116 ) is communicatively coupled with the interstitial space ( 126 ).

GOVERNMENT LICENSE RIGHTS

This invention was made with Government support under HR0011-17-9-0001awarded by Defense Advanced Research Projects Agency. The government hascertain rights in this invention.

TECHNICAL FIELD

The present disclosure relates to conduits for transporting fluids andmethods of fabricating such conduits.

BACKGROUND

Flexible conduits, used in cryogenic propulsion systems, are susceptibleto manufacturing variances and incidental damage. If not timelyidentified, failure of a flexible conduit, such as apressurized-propellant feed line, could potentially lead to damage ofthe main propulsion system.

SUMMARY

Accordingly, apparatuses and methods, intended to address at least theabove-identified concerns, would find utility.

The following is a non-exhaustive list of examples, which may or may notbe claimed, of the subject matter, disclosed herein.

One example of the subject matter, disclosed herein, relates to aconduit for transporting a fluid. The conduit comprises a first collarthat comprises a channel, which is cross-sectionally circumferentiallyclosed, and a second collar. The conduit also comprises a bellows thatcomprises a central axis, a first corrugated outboard ply, a corrugatedinboard ply, interposed between the first corrugated outboard ply andthe central axis, an interstitial space, interposed between thecorrugated inboard ply and the first corrugated outboard ply, and asecond corrugated outboard ply within the interstitial space. Theconduit further comprises a first weld, hermetically interconnecting thecorrugated inboard ply, the first corrugated outboard ply, and the firstcollar. The conduit additionally comprises a second weld, hermeticallyinterconnecting the corrugated inboard ply, the first corrugatedoutboard ply, and the second collar. The conduit also comprises aweld-through ring, located between the corrugated inboard ply and thefirst corrugated outboard ply and coupled to the first collar by thefirst weld. The conduit further comprises a sensor that iscommunicatively coupled with the interstitial space via the channel ofthe first collar. The second corrugated outboard ply is not hermeticallycoupled to the first collar or the second collar.

The conduit provides a compliant structure for transmission of fluids,such as cryogenic fuels, that accommodates displacements encounteredduring operation. A configuration of the weld-through ring and theinterstitial space between the corrugated inboard ply and the corrugatedoutboard ply allows the sensor to monitor conditions within theinterstitial space. In particular, the sensor enables detection of leaksin the corrugated inboard ply by detecting changes in conditions withinthe interstitial space. The first weld promotes a strong, reliable, andsealed connection between the corrugated inboard ply, the firstcorrugated outboard ply, and the first collar. Similarly, the secondweld promotes a strong, reliable, and sealed connection between thecorrugated inboard ply, the first corrugated outboard ply, and thesecond collar. The weld-through ring ensures communicative couplingbetween the interstitial space and the channel of the first collar,which establishes communicative coupling between the sensor and theinterstitial space. Communicatively coupling the interstitial space withthe sensor via the channel allows leaks of fluid or gas into theinterstitial space through the corrugated inboard ply to be detected ata location, external to the first collar. The second corrugated outboardply helps to stiffen the bellows.

Another example of the subject matter, disclosed herein, relates to aconduit for transporting a fluid. The conduit comprises a first collarthat comprises a channel, which is cross-sectionally circumferentiallyclosed. The conduit also comprises a bellows that comprises a centralaxis, a first corrugated outboard ply, and a corrugated inboard ply,interposed between the first corrugated outboard ply and the centralaxis. The bellows additionally comprises an interstitial space,interposed between the corrugated inboard ply and the first corrugatedoutboard ply. The bellows also comprises a second corrugated outboardply, within the interstitial space. The conduit additionally comprises afirst weld, hermetically coupling the corrugated inboard ply, the firstcorrugated outboard ply, and the first collar. The conduit alsocomprises a weld-through ring, located between the corrugated inboardply and the first corrugated outboard ply and coupled to the firstcollar by the first weld. The conduit further comprises a sensor that iscommunicatively coupled with the interstitial space via the channel ofthe first collar. The second corrugated outboard ply is not hermeticallycoupled to the first collar.

The conduit provides a compliant structure for transmission of fluids,such as cryogenic fuels, that accommodates displacements encounteredduring operation. A configuration of the weld-through ring and theinterstitial space between the corrugated inboard ply and the firstcorrugated outboard ply allows the sensor to monitor conditions withinthe interstitial space. In particular, the sensor enables detection ofleaks in the corrugated inboard ply by detecting changes in conditionswithin the interstitial space. The first weld promotes a strong,reliable, and sealed connection between the corrugated inboard ply, thecorrugated first outboard ply, and the first collar. The weld-throughring ensures communicative coupling between the interstitial space andthe channel of the first collar, which establishes communicativecoupling between the sensor and the interstitial space. Communicativelycoupling the interstitial space with the sensor via the channel allowsleaks of fluid or gas into the interstitial space through the corrugatedinboard ply to be detected at a location, external to the first collar.The second corrugated outboard ply helps to stiffen the bellows.

Another example of the subject matter, disclosed herein, relates to amethod of fabricating a conduit. The method comprises simultaneouslycorrugating a first tubular outboard ply, a second tubular outboard ply,inserted into the first tubular outboard ply, and a tubular inboard ply,inserted into the second tubular outboard ply, to form a bellows. Thebellows comprises a central axis, a first corrugated outboard ply, asecond corrugated outboard ply, a corrugated inboard ply, and aninterstitial space, interposed between the corrugated inboard ply andthe first corrugated outboard ply. The first corrugated outboard ply isformed from the first tubular outboard ply, the second corrugatedoutboard ply is formed from the second tubular outboard ply, and thecorrugated inboard ply is formed from the tubular inboard ply. Themethod also comprises simultaneously trimming a firstcorrugated-inboard-ply end of the corrugated inboard ply and a firstfirst-corrugated-outboard-ply end of the first corrugated outboard plyto create a trimmed first corrugated-inboard-ply end of the corrugatedinboard ply and a trimmed first first-corrugated-outboard-ply end of thefirst corrugated outboard ply. The method further comprisessimultaneously trimming a second corrugated-inboard-ply end of thecorrugated inboard ply and a second first-corrugated-outboard-ply end ofthe first corrugated outboard ply to create a trimmed secondcorrugated-inboard-ply end of the corrugated inboard ply and a trimmedsecond first-corrugated-outboard-ply end of the first corrugatedoutboard ply. The method additionally comprises locating a weld-throughring between the corrugated inboard ply and the first corrugatedoutboard ply of the bellows at the trimmed first corrugated-inboard-plyend of the corrugated inboard ply and the trimmed firstfirst-corrugated-outboard-ply end of the first corrugated outboard ply.The method also comprises locating a second weld-through ring betweenthe corrugated inboard ply and the first corrugated outboard ply of thebellows at the trimmed second corrugated-inboard-ply end of thecorrugated inboard ply 110 and the trimmed secondfirst-corrugated-outboard-ply end of the first corrugated outboard ply.The method further comprises simultaneously attaching the trimmed firstcorrugated-inboard-ply end, the trimmed firstfirst-corrugated-outboard-ply end, and the weld-through ring to a firstcollar with a first weld. The method additionally comprisessimultaneously attaching the trimmed second corrugated-inboard-ply end,the trimmed second first-corrugated-outboard-ply end, and the secondweld-through ring to a second collar with a second weld. The method alsocomprises forming a port through the weld-through ring along an axis,parallel with the central axis of the bellows, after attaching theweld-through ring to the first collar with the first weld, so that theport is communicatively coupled with the interstitial space. The methodadditionally comprises forming a second port through the secondweld-through ring along a second axis, parallel with the central axis ofthe bellows, after attaching the second weld-through ring to the secondcollar with the second weld, so that the second port is communicativelycoupled with the interstitial space. The method additionally comprisescommunicatively coupling a sensor with the interstitial space via theport. The method also comprises communicatively coupling a second sensorwith the interstitial space via the second port and a second channelpassing through the second collar.

The method facilitates fabricating the conduit with the sensorconfigured to detect leaks in the corrugated inboard ply of the bellowsof the conduit. Simultaneously corrugating the first tubular outboardply, the second tubular outboard ply, and the tubular inboard ply toform the bellows promotes complementary corrugations in the corrugatedinboard ply, the first corrugated outboard ply, and the secondcorrugated outboard ply of the bellows. The ends of the plies beingunconstrained relative to the first collar and the second collar, helpsreduce stress on the plies of the bellows, during formation of thecorrugations of the bellows, by allowing the plies to be freely slidablerelative to each other as the corrugations are formed. Simultaneouslytrimming the first corrugated-inboard-ply end of the corrugated inboardply and the first first-corrugated-outboard-ply end of the firstcorrugated outboard ply promotes controlled alignment of the trimmedfirst corrugated-inboard-ply end of the corrugated inboard ply and thetrimmed first first-corrugated-outboard-ply end of the first corrugatedoutboard ply. Similarly, simultaneously trimming the secondcorrugated-inboard-ply end of the corrugated inboard ply and the secondfirst-corrugated-outboard-ply end of the first corrugated outboard plypromotes controlled alignment of the trimmed secondcorrugated-inboard-ply end of the corrugated inboard ply and the trimmedsecond first-corrugated-outboard-ply end of the first corrugatedoutboard ply. The weld-through ring facilitates formation of the firstweld while ensuring communicative coupling between the interstitialspace and the channel of the first collar, which establishescommunicative coupling between the sensor and the interstitial space.The second weld-through ring facilitates formation of the second weldwhile ensuring communicative coupling between the interstitial space andthe second channel of the second collar, which establishes communicativecoupling between the second sensor and the interstitial space. The portof the weld-through ring facilitates communicative coupling between theinterstitial space and the channel of the first collar after formationof the first weld. The second port of the second weld-through ringfacilitates communicative coupling between the interstitial space andthe second channel of the second collar after formation of the secondweld. Forming the port after the trimmed first corrugated-inboard-plyend, the trimmed first first-corrugated-outboard-ply end, and theweld-through ring are simultaneously attached to the first collar withthe first weld allows communicative coupling between the interstitialspace and the channel of the first collar after the first weld isformed. Forming the second port after the trimmed secondcorrugated-inboard-ply end, the trimmed secondfirst-corrugated-outboard-ply end, and the second weld-through ring aresimultaneously attached to the second collar with the second weld allowscommunicative coupling between the interstitial space and the secondchannel of the second collar after the second weld is formed.Communicatively coupling the interstitial space with the sensor via theport and the channel passing through the first collar allows leaks offluid or gas into the interstitial space through the corrugated inboardply to be detected at a location, external to the first collar.Communicatively coupling the interstitial space with the second sensorvia the second port and the second channel passing through the secondcollar allows leaks of fluid or gas into the interstitial space throughthe corrugated inboard ply to be detected at a location, external to thesecond collar. The second corrugated outboard ply helps to stiffen thebellows.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus described one or more examples of the present disclosure ingeneral terms, reference will now be made to the accompanying drawings,which are not necessarily drawn to scale, and wherein like referencecharacters designate the same or similar parts throughout the severalviews, and wherein:

FIGS. 1A, 1B, and 1C, collectively, are a block diagram of a conduit fortransporting a fluid, according to one or more examples of the presentdisclosure;

FIG. 2 is a schematic, perspective, sectional view of a first collarportion of the conduit of FIGS. 1A, 1B, and 1C, according to one or moreexamples of the present disclosure;

FIG. 2A is a schematic, perspective, sectional view of a first collarportion of the conduit of FIGS. 1A, 1B, and 1C, according to one or moreexamples of the present disclosure;

FIG. 3 is a schematic, perspective, sectional view of the conduit ofFIGS. 1A, 1B, and 1C, according to one or more examples of the presentdisclosure;

FIG. 3A is a schematic, perspective, sectional view of a second collarportion of the conduit of FIGS. 1A, 1B, and 1C, according to one or moreexamples of the present disclosure;

FIG. 4 is a schematic, perspective, sectional view of a sub-assembly ofthe conduit of FIGS. 1A, 1B, and 1C, according to one or more examplesof the present disclosure;

FIG. 5 is a schematic, perspective, sectional view of a sub-assembly ofthe conduit of FIGS. 1A, 1B, and 1C, according to one or more examplesof the present disclosure;

FIG. 6 is a schematic, perspective, sectional view of a sub-assembly ofthe conduit of FIGS. 1A, 1B, and 1C, according to one or more examplesof the present disclosure;

FIG. 7 is a schematic, perspective, sectional view of a sub-assembly ofthe conduit of FIGS. 1A, 1B, and 1C, according to one or more examplesof the present disclosure;

FIG. 8 is a schematic, perspective, sectional view of a sub-assembly ofthe conduit of FIGS. 1A, 1B, and 1C, according to one or more examplesof the present disclosure;

FIG. 9 is a schematic, perspective, sectional view of a sub-assembly ofthe conduit of FIGS. 1A, 1B, and 1C, according to one or more examplesof the present disclosure;

FIG. 10 is a schematic, perspective, sectional view of a sub-assembly ofthe conduit of FIGS. 1A, 1B, and 1C, according to one or more examplesof the present disclosure;

FIGS. 11A-11D, collectively, are a block diagram of a method offabricating a conduit of FIGS. 1A, 1B, and 1C, according to one or moreexamples of the present disclosure;

FIG. 12 is a block diagram of aircraft production and servicemethodology; and

FIG. 13 is a schematic illustration of an aircraft.

DETAILED DESCRIPTION

In FIGS. 1A, 1B, and 1C, referred to above, solid lines, if any,connecting various elements and/or components may represent mechanical,electrical, fluid, optical, electromagnetic and other couplings and/orcombinations thereof. As used herein, “coupled” means associateddirectly as well as indirectly. For example, a member A may be directlyassociated with a member B, or may be indirectly associated therewith,e.g., via another member C. It will be understood that not allrelationships among the various disclosed elements are necessarilyrepresented. Accordingly, couplings other than those depicted in theblock diagrams may also exist. Dashed lines, if any, connecting blocksdesignating the various elements and/or components represent couplingssimilar in function and purpose to those represented by solid lines;however, couplings represented by the dashed lines may either beselectively provided or may relate to alternative examples of thepresent disclosure. Likewise, elements and/or components, if any,represented with dashed lines, indicate alternative examples of thepresent disclosure. One or more elements shown in solid and/or dashedlines may be omitted from a particular example without departing fromthe scope of the present disclosure. Environmental elements, if any, arerepresented with dotted lines. Virtual (imaginary) elements may also beshown for clarity. Those skilled in the art will appreciate that some ofthe features illustrated in FIGS. 1A, 1B, and 1C may be combined invarious ways without the need to include other features described inFIGS. 1A, 1B, and 1C, other drawing figures, and/or the accompanyingdisclosure, even though such combination or combinations are notexplicitly illustrated herein. Similarly, additional features notlimited to the examples presented, may be combined with some or all ofthe features shown and described herein.

In FIGS. 11A-11D and 12, referred to above, the blocks may representoperations and/or portions thereof and lines connecting the variousblocks do not imply any particular order or dependency of the operationsor portions thereof. Blocks represented by dashed lines indicatealternative operations and/or portions thereof. Dashed lines, if any,connecting the various blocks represent alternative dependencies of theoperations or portions thereof. It will be understood that not alldependencies among the various disclosed operations are necessarilyrepresented. FIGS. 11A-11D and 12 and the accompanying disclosuredescribing the operations of the method(s) set forth herein should notbe interpreted as necessarily determining a sequence in which theoperations are to be performed. Rather, although one illustrative orderis indicated, it is to be understood that the sequence of the operationsmay be modified when appropriate. Accordingly, certain operations may beperformed in a different order or simultaneously. Additionally, thoseskilled in the art will appreciate that not all operations describedneed be performed.

In the following description, numerous specific details are set forth toprovide a thorough understanding of the disclosed concepts, which may bepracticed without some or all of these particulars. In other instances,details of known devices and/or processes have been omitted to avoidunnecessarily obscuring the disclosure. While some concepts will bedescribed in conjunction with specific examples, it will be understoodthat these examples are not intended to be limiting.

Unless otherwise indicated, the terms “first,” “second,” etc. are usedherein merely as labels, and are not intended to impose ordinal,positional, or hierarchical requirements on the items to which theseterms refer. Moreover, reference to, e.g., a “second” item does notrequire or preclude the existence of, e.g., a “first” or lower-numbereditem, and/or, e.g., a “third” or higher-numbered item.

Reference herein to “one example” means that one or more feature,structure, or characteristic described in connection with the example isincluded in at least one implementation. The phrase “one example” invarious places in the specification may or may not be referring to thesame example.

As used herein, a system, apparatus, structure, article, element,component, or hardware “configured to” perform a specified function isindeed capable of performing the specified function without anyalteration, rather than merely having potential to perform the specifiedfunction after further modification. In other words, the system,apparatus, structure, article, element, component, or hardware“configured to” perform a specified function is specifically selected,created, implemented, utilized, programmed, and/or designed for thepurpose of performing the specified function. As used herein,“configured to” denotes existing characteristics of a system, apparatus,structure, article, element, component, or hardware which enable thesystem, apparatus, structure, article, element, component, or hardwareto perform the specified function without further modification. Forpurposes of this disclosure, a system, apparatus, structure, article,element, component, or hardware described as being “configured to”perform a particular function may additionally or alternatively bedescribed as being “adapted to” and/or as being “operative to” performthat function.

Illustrative, non-exhaustive examples, which may or may not be claimed,of the subject matter according the present disclosure are providedbelow.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2-3A, conduit 100 for transporting a fluid is disclosed. Conduit 100comprises first collar 102 that comprises channel 118, which iscross-sectionally circumferentially closed, and second collar 103.Conduit 100 also comprises bellows 108 that comprises central axis 180,first corrugated outboard ply 114, corrugated inboard ply 110,interposed between first corrugated outboard ply 114 and central axis180, interstitial space 126, interposed between corrugated inboard ply110 and first corrugated outboard ply 114, and second corrugatedoutboard ply 112 within interstitial space 126. Conduit 100 furthercomprises first weld 138, hermetically interconnecting corrugatedinboard ply 110, first corrugated outboard ply 114, and first collar102. Conduit 100 additionally comprises second weld 183, hermeticallyinterconnecting corrugated inboard ply 110, first corrugated outboardply 114, and second collar 103. Conduit 100 also comprises weld-throughring 150, located between corrugated inboard ply 110 and firstcorrugated outboard ply 114 and coupled to first collar 102 by firstweld 138. Conduit 100 further comprises sensor 116 that iscommunicatively coupled with interstitial space 126 via channel 118 offirst collar 102. Second corrugated outboard ply 112 is not hermeticallycoupled to first collar 102 or second collar 103. The preceding subjectmatter of this paragraph characterizes example 1 of the presentdisclosure.

Conduit 100 provides a compliant structure for transmission of fluids,such as cryogenic fuels, that accommodates displacements encounteredduring operation. A configuration of weld-through ring 150 andinterstitial space 126 between corrugated inboard ply 110 and firstcorrugated outboard ply 114 allows sensor 116 to monitor conditionswithin interstitial space 126. In particular, sensor 116 enablesdetection of leaks in corrugated inboard ply 110 by detecting changes inconditions within interstitial space 126. First weld 138 promotes astrong, reliable, and sealed connection between corrugated inboard ply110, first corrugated outboard ply 114, and first collar 102. Similarly,second weld 183 promotes a strong, reliable, and sealed connectionbetween corrugated inboard ply 110, first corrugated outboard ply 114,and second collar 103. Weld-through ring 150 ensures communicativecoupling between interstitial space 126 and channel 118 of first collar102, which establishes communicative coupling between sensor 116 andinterstitial space 126. Communicatively coupling interstitial space 126with sensor 116 via channel 118 allows fluid or gas that has leaked intointerstitial space 126 through corrugated inboard ply 110 to be detectedat a location, external to first collar 102. Second corrugated outboardply 112 helps to stiffen bellows 108.

First weld 138 and second weld 183 help to respectively hermeticallycouple first end 160 of bellows 108 to first collar 102 and second end162 of bellows 108, which is axially opposite first end 160 of bellows,to second collar 103. In some examples, each of first weld 138 andsecond weld 183 is a homogenous weld that includes filler material.Other welds of conduit 100 are homogenous welds in certain examples.Homogenous welds are helpful when welding relatively thin parts, such ascorrugated inboard ply 110 and first corrugated outboard ply 114. In oneor more examples, the filler material is a material with propertiessimilar to those of the material of first collar 102 and second collar103. According to certain examples, each of first collar 102, secondcollar 103, corrugated inboard ply 110, first corrugated outboard ply114, and second corrugated outboard ply 112, is made of an austeniticnickel-chromium-based superalloy, such as Inconel®. Each of corrugatedinboard ply 110, first corrugated outboard ply 114, and secondcorrugated outboard ply 112 has a thickness of about 0.012 inches, insome examples.

According to some examples, one or both of first collar 102 and secondcollar 103 is manufactured using subtractive manufacturing techniques,such as machining. In other examples, one or both of first collar 102and second collar 103 is manufactured using additive manufacturingtechniques. In yet other examples, one or both of first collar 102 andsecond collar 103 is manufactured using forging or casting techniques.

In some examples, first collar 102 is different than second collar 103.In one or more examples, first fluid flow port 132 of first collar 102is of a first type, for fluidly coupling to a first component, andsecond fluid flow port 133 of second collar 103 is of a second type, forfluidly coupling to a second component, different than the firstcomponent. Each of first fluid flow port 132 and second fluid flow port133 defines an aperture through which fluid flows into or out of conduit100. In some examples, one of first fluid flow port 132 or second fluidflow port 133 is a nozzle.

Bellows 108 comprises corrugations 158 that help to facilitatecompliance of bellows 108. For example, corrugations 158 allow bellows108 to expand and retract, radially and longitudinally, relative tocentral axis 180, in response to changes in internal and externalconditions relative to conduit 100 (e.g., changes in pressure,temperature, and geometry). Additionally, bellows 108 defines fluid flowchannel 128, through which fluid is flowable.

In one or more examples, sensor 116 is any one of various sensors usedto detect the presence of a chemical or a pressure change. In one ofmore examples, sensor 116 is one or more of a micro-fuel cell,contactless oxygen sensor spots, oxygen sensor foil, and oxygen probes.

Welds are continuous or annular shaped in one or more examples.Additionally, in one or more example, welds have closed shapes. As usedherein, “hermetically coupled with a weld” means the weld is continuousand forms a closed shape.

As used in relation to channel 118, which is, for example, a port or ahole, “cross-sectionally circumferentially closed” means that thecircumference of any cross-section of channel 118 that lies in a plane,perpendicular to a central axis of channel 118, has a closed shape. Aclosed shape is a space that is fully enclosed by an unbroken line orcontour.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,conduit 100 further comprises tapered spacer 148, located withininterstitial space 126. Tapered spacer 148 abuts weld-through ring 150.The preceding subject matter of this paragraph characterizes example 2of the present disclosure, wherein example 2 also includes the subjectmatter according to example 1, above.

Tapered spacer 148 helps to maintain spacing between corrugated inboardply 110 and first corrugated outboard ply 114 at a location, adjacentweld-through ring 150. More specifically, tapered spacer 148 helps toprevent corrugated inboard ply 110 from sharply collapsing aroundweld-through ring 150 when conduit 100 is pressurized, which canintroduce undesirable stress risers.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,tapered spacer 148 is coextensive with at least a portion of firstcollar 102 along central axis 180 of bellows 108. The preceding subjectmatter of this paragraph characterizes example 3 of the presentdisclosure, wherein example 3 also includes the subject matter accordingto example 2, above.

Tapered spacer 148, being coextensive with at least a portion of firstcollar 102 along central axis 180 of bellows 108, helps to preventstress risers from forming, in corrugated inboard ply 110 of bellows108, within the bounds of first collar 102.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,tapered spacer 148 is tubular. Tapered spacer 148 comprisesfull-thickness end 147, abutting weld-through ring 150 and having athickness equal to that of weld-through ring 150. Tapered spacer 148also comprises reduced-thickness end 149, spaced apart from and oppositefull-thickness end 147 and having a thickness less than that ofweld-through ring 150. Tapered spacer 148 further comprises innersurface 173, facing central axis 180 and oblique relative to centralaxis 180. Inner surface 173 tapers radially outwardly relative tocentral axis 180 in a direction away from weld-through ring 150 alongcentral axis 180. The preceding subject matter of this paragraphcharacterizes example 4 of the present disclosure, wherein example 4also includes the subject matter according to example 2 or 3, above.

Full-thickness end 147 of tapered spacer 148, abutting weld-through ring150, ensures corrugated inboard ply 110 does not collapse at locationbetween tapered spacer 148 and weld-through ring 150 when conduit 100 ispressurized. Inner surface 173 of tapered spacer 148, tapering radiallyoutwardly relative to central axis 180 in a direction away fromweld-through ring 150 along central axis 180 toward reduced-thicknessend 149, promotes a gradual reduction of the distance between corrugatedinboard ply 110 and first corrugated outboard ply 114, or the size ofinterstitial space 126, when conduit 100 is pressurized, which helpsreduce stress risers in corrugated inboard ply 110. The distance betweencorrugated inboard ply 110 and first corrugated outboard ply 114 reducesfrom a distance equal to a thickness T of weld-through ring 150.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,inner surface 173 of tapered spacer 148 has a linear taper. Thepreceding subject matter of this paragraph characterizes example 5 ofthe present disclosure, wherein example 5 also includes the subjectmatter according to example 4, above.

Taper of inner surface 173 of tapered spacer 148, being linear, promotesa constant reduction of the distance between corrugated inboard ply 110and first corrugated outboard ply 114 when conduit 100 is pressurized,which helps to maintain a constant stress on corrugated inboard ply 110along tapered spacer 148 when conduit 100 is pressurized.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,inner surface 173 of tapered spacer 148 has a non-linear taper. Thepreceding subject matter of this paragraph characterizes example 6 ofthe present disclosure, wherein example 6 also includes the subjectmatter according to example 4, above.

Taper of inner surface 173 of tapered spacer 148, being non-linear,promotes a reduction of the distance between corrugated inboard ply 110and first corrugated outboard ply 114 at a varying rate when conduit 100is pressurized, which helps to vary the stress on corrugated inboard ply110 along tapered spacer 148 when conduit 100 is pressurized. In someexamples, a non-linear taper is a concave taper, a convex taper, or anundulating taper.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,inner surface 173 of tapered spacer 148 tapers to a knife edge. Thepreceding subject matter of this paragraph characterizes example 7 ofthe present disclosure, wherein example 7 also includes the subjectmatter according to any one of examples 4 to 6, above.

Tapering inner surface 173 of tapered spacer 148 to a knife edge helpsto smooth the transition of corrugated inboard ply 110 from taperedspacer 148 to first corrugated outboard ply 114 when conduit 100 ispressurized, which assists in reducing stress risers in corrugatedinboard ply 110. As used herein, a knife edge is an edge wherein twosurfaces, oblique to each other, terminate. In one or more examples, thetwo oblique surfaces have an acute included angle.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,bellows 108 comprises fluid flow channel 128, at least partially definedby corrugated inboard ply 110. A portion of corrugated inboard ply 110,in contact with tapered spacer 148, is configured to geometricallyconform to inner surface 173 of tapered spacer 148 when fluid flowchannel 128 is pressurized. The preceding subject matter of thisparagraph characterizes example 8 of the present disclosure, whereinexample 8 also includes the subject matter according to any one ofexamples 4 to 7, above.

A portion of corrugated inboard ply 110, in contact with tapered spacer148, geometrically conforming to tapered spacer 148 when fluid flowchannel 128 of bellows 108 is pressurized promotes a gradual reductionof the distance between corrugated inboard ply 110 and first corrugatedoutboard ply 114, or the size of interstitial space 126, which helpsreduce stress risers in corrugated inboard ply 110.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,tapered spacer 148 is made of a permeable material. The precedingsubject matter of this paragraph characterizes example 9 of the presentdisclosure, wherein example 9 also includes the subject matter accordingto any one of examples 2 to 8, above.

The permeable material of tapered spacer 148, which allows for thepassing of liquids or gases to pass through the permeable material,enables changes in pressure or chemical composition in interstitialspace 126 to reach channel 118 and thus sensor 116. As used herein, apermeable material is a material through which a fluid is able to flow.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,weld-through ring 150 is interposed between channel 118 and taperedspacer 148. The preceding subject matter of this paragraph characterizesexample 10 of the present disclosure, wherein example 10 also includesthe subject matter according to any one of examples 2 to 9, above.

Weld-through ring 150, interposed between channel 118 and tapered spacer148, ensures corrugated inboard ply 110 does not collapse at channel118, when conduit 100 is pressured, which facilitates communicativecoupling between channel 118 and interstitial space 127.

Referring generally to FIG. 1A and particularly to, e.g., FIG. 2-3,weld-through ring 150 comprises port 188, passing through weld-throughring 150. Port 188 communicatively couples channel 118 with interstitialspace 126. The preceding subject matter of this paragraph characterizesexample 11 of the present disclosure, wherein example 11 also includesthe subject matter according to any one of examples 1 to 9, above.

Port 188 of weld-through ring 150 facilitates communicative couplingbetween interstitial space 126 and channel 118 of first collar 102through weld-through ring 150. Accordingly, port 188 of weld-throughring 150 enables welding of first corrugated outboard ply 114 andcorrugated inboard ply 110 to first collar 102 with the same weldwithout affecting the ability of sensor 116 to detect conditions withininterstitial space 126.

Referring generally to FIG. 1A and particularly to, e.g., FIG. 2-3, port188 is parallel with central axis 180 of bellows 108. The precedingsubject matter of this paragraph characterizes example 12 of the presentdisclosure, wherein example 12 also includes the subject matteraccording to example 11, above.

Port 188 of weld-through ring 150, being parallel with central axis 180of bellows 108, enables access to interstitial space 126 withoutaffecting integrity of first weld 138.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second collar 103 comprises second channel 119, which iscross-sectionally circumferentially closed. Conduit 100 furthercomprises second weld-through ring 157, located between corrugatedinboard ply 110 and first corrugated outboard ply 114 and coupled tosecond collar 103 by second weld 183. Conduit 100 additionally comprisessecond sensor 117 that is communicatively coupled with interstitialspace 126 via second channel 119 of second collar 103. The precedingsubject matter of this paragraph characterizes example 13 of the presentdisclosure, wherein example 13 also includes the subject matteraccording to any one of examples 1 to 12, above.

A configuration of second weld-through ring 157 and interstitial space126 between corrugated inboard ply 110 and first corrugated outboard ply114 allows second sensor 117 to monitor conditions within interstitialspace 126. In particular, second sensor 117 enables detection of leaksin corrugated inboard ply 110 by detecting changes in conditions withininterstitial space 126. Second weld-through ring 157 ensurescommunicative coupling between interstitial space 126 and second channel119 of second collar 103, which establishes communicative couplingbetween second sensor 117 and interstitial space 126. Communicativelycoupling interstitial space 126 with second sensor 117 via secondchannel 119 allows leaks of fluid or gas into interstitial space 126through corrugated inboard ply 110 to be detected at a location,external to second collar 103. Additionally, second sensor 117, beingcommunicatively coupled with interstitial space 126 along with sensor116, promotes redundant detection of leakage through corrugated inboardply 110. In one or more examples, second sensor 117 is able to detect achange in pressure or chemical composition in interstitial space 126that is not detectable by sensor 116 for various reasons, such as, forexample, when fluid, leaking through corrugated inboard ply 110, doesnot reach sensor 116 or when sensor 116 is disabled.

As used in relation to second channel 119, which is, for example, a portor a hole, “cross-sectionally circumferentially closed” means that thecircumference of any cross-section of second channel 119 that lies in aplane, perpendicular to a central axis of second channel 119, has aclosed shape.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, conduit 100 further comprises second tapered spacer 181, locatedwithin interstitial space 126. Second tapered spacer 181 abuts secondweld-through ring 157. The preceding subject matter of this paragraphcharacterizes example 14 of the present disclosure, wherein example 14also includes the subject matter according to example 13, above.

Second tapered spacer 181 helps to maintain spacing between corrugatedinboard ply 110 and first corrugated outboard ply 114 at a location,adjacent second weld-through ring 157. More specifically, second taperedspacer 181 helps to prevent corrugated inboard ply 110 from sharplycollapsing around second weld-through ring 157 when conduit 100 ispressurized, which can introduce undesirable stress risers.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second tapered spacer 181 is coextensive with at least a portion ofsecond collar 103 along central axis 180 of bellows 108. The precedingsubject matter of this paragraph characterizes example 15 of the presentdisclosure, wherein example 15 also includes the subject matteraccording to example 14, above.

Second tapered spacer 181, being coextensive with at least a portion ofsecond collar 103 along central axis 180 of bellows 108, helps toprevent stress risers from forming, in corrugated inboard ply 110 ofbellows 108, within the bounds of second collar 103.

Referring generally to FIGS. 3 and 3A and particularly to, e.g., FIGS. 3and 3A, second tapered spacer 181 is tubular. Second tapered spacer 181comprises second full-thickness end 159, abutting second weld-throughring 157 and having a thickness equal to that of second weld-throughring 157, second reduced-thickness end 195, spaced apart from andopposite second full-thickness end 159 and having a thickness less thanthat of second weld-through ring 157, and second inner surface 175,facing central axis 180 and oblique relative to central axis 180. Secondinner surface 175 tapers radially outwardly relative to central axis 180in a direction away from second weld-through ring 157 along central axis180. The preceding subject matter of this paragraph characterizesexample 16 of the present disclosure, wherein example 16 also includesthe subject matter according to example 14 or 15, above.

Second full-thickness end 159 of second tapered spacer 181, abuttingsecond weld-through ring 157, ensures corrugated inboard ply 110 doesnot collapse at location between second tapered spacer 181 and secondweld-through ring 157 when conduit 100 is pressurized. Second innersurface 175 of second tapered spacer 181, tapering radially outwardlyrelative to central axis 180 in a direction away from secondweld-through ring 157 along central axis 180 toward secondreduced-thickness end 195, promotes a gradual reduction of the distancebetween corrugated inboard ply 110 and first corrugated outboard ply114, or the size of interstitial space 126, which helps reduce stressrisers in corrugated inboard ply 110. The distance between corrugatedinboard ply 110 and first corrugated outboard ply 114 reduces from adistance equal to a thickness T2 of second weld-through ring 157

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second inner surface 175 of second tapered spacer 181 has a lineartaper. The preceding subject matter of this paragraph characterizesexample 17 of the present disclosure, wherein example 17 also includesthe subject matter according to example 16, above.

Taper of second inner surface 175 of second tapered spacer 181, beinglinear, promotes a constant reduction of the distance between corrugatedinboard ply 110 and first corrugated outboard ply 114 when conduit 100is pressurized, which helps to maintain a constant stress on corrugatedinboard ply 110 along second tapered spacer 181 when conduit 100 ispressurized.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second inner surface 175 of second tapered spacer 181 has anon-linear taper. The preceding subject matter of this paragraphcharacterizes example 18 of the present disclosure, wherein example 18also includes the subject matter according to example 16, above.

Taper of second inner surface 175 of second tapered spacer 181, beingnon-linear, promotes a reduction of the distance between corrugatedinboard ply 110 and second corrugated outboard ply 112 at a varying ratewhen conduit 100 is pressurized, which helps to vary the stress oncorrugated inboard ply 110 along second tapered spacer 181 when conduit100 is pressurized.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second inner surface of second tapered spacer tapers to a knifeedge. The preceding subject matter of this paragraph characterizesexample 19 of the present disclosure, wherein example 19 also includesthe subject matter according to any one of examples 16 to 18, above.

Tapering second inner surface 175 of second tapered spacer 181 to aknife edge helps to smooth the transition of corrugated inboard ply 110from second tapered spacer 181 to second corrugated outboard ply 112when conduit 100 is pressurized, which assists in reducing stress risersin corrugated inboard ply 110.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, bellows 108 comprises fluid flow channel 128, at least partiallydefined by corrugated inboard ply 110. A portion of corrugated inboardply 110, in contact with second tapered spacer 181, is configured togeometrically conform to second inner surface 175 of second taperedspacer 181 when fluid flow channel 128 is pressurized. The precedingsubject matter of this paragraph characterizes example 20 of the presentdisclosure, wherein example 20 also includes the subject matteraccording to any one of examples 16 to 19, above.

A portion of corrugated inboard ply 110, in contact with second taperedspacer 181, geometrically conforming to second tapered spacer 181 whenfluid flow channel 128 of bellows 108 is pressurized promotes a gradualreduction of the distance between corrugated inboard ply 110 and secondcorrugated outboard ply 112, or the size of interstitial space 126, whenconduit 100 is pressurized, which helps reduce stress risers incorrugated inboard ply 110.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second tapered spacer 181 is made of a permeable material. Thepreceding subject matter of this paragraph characterizes example 21 ofthe present disclosure, wherein example 21 also includes the subjectmatter according to any one of examples 14 to 20, above.

The permeable material of second tapered spacer 181, which allows forthe passing of liquids or gases to pass through the permeable material,enables changes in pressure or chemical composition in interstitialspace 126 to reach second channel 119 and thus second sensor 117.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second weld-through ring 157 is interposed between second channel119 and second tapered spacer 181. The preceding subject matter of thisparagraph characterizes example 22 of the present disclosure, whereinexample 22 also includes the subject matter according to any one ofexamples 14 to 21, above.

Second weld-through ring 157, interposed between second channel 119 andsecond tapered spacer 181, ensures corrugated inboard ply 110 does notcollapse at second channel 119, when conduit 100 is pressured, whichfacilitates communicative coupling between second channel 119 andinterstitial space 127.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second weld-through ring 157 comprises second port 191, passingthrough second weld-through ring 157. Second port 191 communicativelycouples second channel 119 with interstitial space 126. The precedingsubject matter of this paragraph characterizes example 23 of the presentdisclosure, wherein example 23 also includes the subject matteraccording to any one of examples 13 to 22, above.

Second port 191 of second weld-through ring 157 facilitatescommunicative coupling between interstitial space 126 and second channel119 of second collar 103. Accordingly, port 188 of weld-through ring 150enables welding of first corrugated outboard ply 114 and corrugatedinboard ply 110 to second collar 103 with the same weld withoutaffecting the ability of second sensor 117 to detect conditions withininterstitial space 126.

Referring generally to FIG. 1B and particularly to, e.g., FIGS. 3 and3A, second port 191 is parallel with central axis 180 of bellows 108.The preceding subject matter of this paragraph characterizes example 24of the present disclosure, wherein example 24 also includes the subjectmatter according to example 23, above.

Second port 191 of second weld-through ring 157, being parallel withcentral axis 180 of bellows 108, enables access to interstitial space126 without affecting integrity of second weld 183.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2-3A, first collar 102 is a single-piece structure. Second collar is asingle-piece structure. The preceding subject matter of this paragraphcharacterizes example 25 of the present disclosure, wherein example 25also includes the subject matter according to any one of examples 1 to24, above.

First collar 102, being a single-piece, monolithic structure, and secondcollar 103, being a single-piece, monolithic structure, simplifies thefabrication of conduit 100 and promotes strength and reliability offirst collar 102 and second collar 103, since joining of multiple piecesto form first collar 102 and second collar 103 via welding or otherwiseis avoided. As used herein, a single-piece structure is monolithic ormade of only one piece, rather than several pieces joined together.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2-3A and 7-10, first collar 102 comprises first annular pocket 164. Aportion of corrugated inboard ply 110, a portion of first corrugatedoutboard ply 114, and a portion of weld-through ring 150 are locatedwithin first annular pocket 164 of first collar 102. The precedingsubject matter of this paragraph characterizes example 26 of the presentdisclosure, wherein example 26 also includes the subject matteraccording to any one of examples 1 to 25, above.

First annular pocket 164 helps to receive, retain, and align corrugatedinboard ply 110, first corrugated outboard ply 114, and weld-throughring 150 for welding to first collar 102. Similarly, second annularpocket 193 helps to receive, retain, and align corrugated inboard ply110 and first corrugated outboard ply 114 for welding to second collar103.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, conduit 100 further comprises sheath 130 that comprisesreinforcement layer 187. First corrugated outboard ply 114 is interposedbetween sheath 130 and central axis 180. The preceding subject matter ofthis paragraph characterizes example 27 of the present disclosure,wherein example 27 also includes the subject matter according to any oneof examples 1 to 26, above.

Reinforcement layer 187 of sheath 130 helps to protect bellows 108 fromexternal objects.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, sheath 130 is coupled to first collar 102 and to second collar103. The preceding subject matter of this paragraph characterizesexample 28 of the present disclosure, wherein example 28 also includesthe subject matter according to example 27, above.

Coupling sheath 130 to first collar 102 and second collar 103 ensuresouter periphery of bellows 108, in its entirety, is protected.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, sheath 130 is movable relative to first collar 102 and relativeto second collar 103. The preceding subject matter of this paragraphcharacterizes example 29 of the present disclosure, wherein example 29also includes the subject matter according to example 28, above.

Sheath 130, being movable relative to first collar 102 and second collar103, facilitates compliance of sheath 130 relative to bellows 108 byallowing sheath 130 to move with bellows 108 during use of conduit 100.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, sheath 130 is translatable along central axis 180 relative tofirst collar 102 and relative to second collar 103. The precedingsubject matter of this paragraph characterizes example 30 of the presentdisclosure, wherein example 30 also includes the subject matteraccording to example 29, above.

Sheath 130, being translatable along central axis 180 relative to firstcollar 102, accommodates lengthening e.g., expansion and shorteninge.g., contraction of bellows 108 during use of conduit 100.

In some examples, sheath 130 is coupled to each of first collar 102 andsecond collar 103 by pins 169 engaged with slots 167 formed in firstcollar 102 and second collar. Each one of slots 167 is elongated alongcentral axis 180. Each of pins 169 passes through a corresponding end ofsheath 130 and passes into a corresponding one of slots 167. Sheath 130is non-movably fixed to pins 169, but each of pins 169 is allowed totranslatably move along the corresponding one of slots 167, whichfacilitates translational movement of sheath 130 along central axis 180relative to first collar 102 and second collar 103. According to oneexample, each one of slots 167 has a width, substantially equal to awidth of pins 169, which prevents pins 169, and thus sheath 130, fromrotating about central axis 180 relative to first collar 102 and secondcollar 103.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, sheath 130 is rotatable about central axis 180 relative tofirst collar 102 and relative to second collar 103. The precedingsubject matter of this paragraph characterizes example 31 of the presentdisclosure, wherein example 31 also includes the subject matteraccording to example 29 or 30, above.

Sheath 130, being rotatable about central axis 180 relative to firstcollar 102 and second collar 103, accommodates rotation of bellows 108about central axis 180 during use of conduit 100.

In some examples, slots 167 formed in first collar 102 and second collar103, are at least partially annular. Accordingly, pins 169, when engagedwith slots 167, are allowed to move translatably along slots 167 in acircumferential direction relative to first collar 102 and second collar103. Such movement of pins 169 within slots 167 facilitates rotationalmovement of sheath 130 about central axis 180 relative to first collar102 and second collar 103. According to one example, each one of slots167 has a width that is substantially equal to a width of each one ofpins 169, which prevents pins 169, and thus sheath 130, from translatingalong central axis 180 relative to first collar 102 and second collar103. However, in at least one other example, each one of slots 167 has awidth that is greater than the width of each one of pins 169. Each oneof slots 167, having a width that is greater than the width of each oneof pins 169, accommodates both rotational movement of sheath 130 aboutcentral axis 180 relative to first collar 102 and second collar 103 andtranslational movement of sheath 130 along central axis 180 relative tofirst collar 102 and second collar 103.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, sheath 130 further comprises low-friction layer 189, interposedbetween reinforcement layer 187 of sheath 130 and first corrugatedoutboard ply 114 of bellows 108. Low-friction layer 189 of sheath 130has a surface roughness lower than that of reinforcement layer 187 ofsheath 130. The preceding subject matter of this paragraph characterizesexample 32 of the present disclosure, wherein example 32 also includesthe subject matter according to any one of examples 27 to 31, above.

Low-friction layer 189 of sheath 130 helps to reduce abrasions betweenreinforcement layer 187 and bellows 108, particularly when bellows 108moves relative to sheath 130.

According to some examples, the surface roughness of low-friction layer189 corresponds with a coefficient-of-friction of the low-friction layer189 between 0.05 and 0.1, and the surface roughness of reinforcementlayer 187 corresponds with a coefficient-of-friction that is higher thanthat of low-friction layer 189. Low-friction layer 189 of sheath 130 ismade of a low-friction material, such as polytetrafluoroethylene,Nylon®, Teflon®, and the like, in some examples. Reinforcement layer 187is made of a high-abrasion-resistance material, such as fiberglass,aramid, stainless steel (mesh), in certain examples.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, low-friction layer 189 of sheath 130 is in contact with firstcorrugated outboard ply 114 of bellows 108. The preceding subject matterof this paragraph characterizes example 33 of the present disclosure,wherein example 33 also includes the subject matter according to example32, above.

Low-friction layer 189 of sheath 130, being in contact with firstcorrugated outboard ply 114, ensures that the outside diameter of sheath130 is as small as possible for use in confined spaces.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3A,pressure in interstitial space 126 and in channel 118 is no more than 15pounds per square inch (psi). The preceding subject matter of thisparagraph characterizes example 34 of the present disclosure, whereinexample 34 also includes the subject matter according to any one ofexamples 1 to 33, above.

When conduit 100 is used in space, maintaining pressure in interstitialspace 126 at or below 15 psi provides controlled separation betweencorrugated inboard ply 110, first corrugated outboard ply 114, andsecond corrugated outboard ply 112, which prevents corrugated inboardply 110, first corrugated outboard ply 114, and second corrugatedoutboard ply 112 from pressing against each other excessively.Preventing corrugated inboard ply 110, first corrugated outboard ply114, and second corrugated outboard ply 112 from pressing against eachother excessively helps facilitate transfer, to first sensor 116, of anyfluid (e.g., propellant) that has leaked into interstitial space 126. Asused herein, pounds per square inch (psi) is absolute pressure.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3A,pressure in interstitial space 126 and in channel 118 is no more than 5psi. The preceding subject matter of this paragraph characterizesexample 35 of the present disclosure, wherein example 35 also includesthe subject matter according example 34, above.

Maintaining pressure in interstitial space 126 at or below 5 psi ensurespressure in interstitial space 126 is not excessive when conduit 100 isused in space. Additionally, providing some pressure at or below 5 psiin interstitial space 126 provides some controlled separation betweencorrugated inboard ply 110 and first corrugated outboard ply 114.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3A,sensor 116 is configured to detect a pressure change in interstitialspace 126. The preceding subject matter of this paragraph characterizesexample 36 of the present disclosure, wherein example 36 also includesthe subject matter according to any one of examples 1 to 35, above.

Pressurized fluid leaking from corrugated inboard ply 110 can cause achange in pressure in interstitial space 126. Sensor 116, beingconfigured to detect a pressure change in interstitial space 126, allowsleakage of fluid from corrugated inboard ply 110 to be detected.Furthermore, in some examples, sensor 116, being configured to detect apressure change in interstitial space 126, is agnostic to the type offluid transmitted through conduit 100 and leaking from corrugatedinboard ply 110, which helps to increase the versatility of conduit 100.

Referring generally to FIGS. 1A and 1C and particularly to, e.g., FIGS.2-3A, sensor 116 is configured to detect a chemical change ininterstitial space 126. The preceding subject matter of this paragraphcharacterizes example 37 of the present disclosure, wherein example 37also includes the subject matter according to any one of examples 1 to35, above.

Sensor 116, being configured to detect a change in chemical compositionin interstitial space 126, allows leakage of fluid from corrugatedinboard ply 110 to be detected. Furthermore, in some examples, sensor116, being configured to detect a change in chemical composition ininterstitial space 126, is agnostic to the pressure of fluid transmittedthrough conduit 100 and pressure of fluid in interstitial space 126,which helps to increase the versatility of conduit 100.

Referring generally to FIGS. 1A and 1C and particularly to, e.g., FIG.10, sensor 116 comprises first chamber 190, containing first reactant198, and second chamber 192, containing second reactant 199. Secondchamber 192 is isolated from first chamber 190 and is communicativelycoupled with channel 118 of first collar 102. First reactant 198 isidentical to second reactant 199. The preceding subject matter of thisparagraph characterizes example 38 of the present disclosure, whereinexample 38 also includes the subject matter according to example 37,above.

First reactant 198, being the same as second reactant 199, facilitatescontrasting visual conditions if first reactant 198 reacts with gasleaking into interstitial space 126. Because first reactant 198 andsecond reactant 199 are the same, the contrasting visual conditionsoccur despite changes in lighting conditions or discoloration of firstreactant 198 and second reactant 199 due to time or atmosphericconditions. Contrasting visual conditions is enhanced by configuringfirst chamber 190 and second chamber 192 in a side-by-sideconfiguration.

Referring generally to FIG. 1A and particularly to, e.g., FIGS. 2-3,channel 118 comprises first portion 118A and second portion 118B,perpendicular to first portion 118A. The preceding subject matter ofthis paragraph characterizes example 39 of the present disclosure,wherein example 39 also includes the subject matter according to any oneof examples 1 to 38, above.

Channel 118, having first portion 118A and second portion 118B, enablespositioning of sensor 116 radially, or perpendicularly relative tocentral axis 180, relative to first collar 102, rather than axially, orparallel to central axis 180, relative to first collar 102. Similarly,second channel 119, having third portion 119A and fourth portion 119Bthat is perpendicular to first portion 118A, enables positioning ofsecond sensor 117 radially, or perpendicularly relative to central axis180, relative to second collar 103, rather than axially, or parallel tocentral axis 180, relative to second collar 103.

In some examples, second portion 118B is co-axial with port 188 andfirst portion 118A is obtuse or perpendicular relative to second portion118B. Second portion 118B is formed concurrently with port 188, in someexamples. Similarly, in some examples, fourth portion 119B of secondchannel 119 is co-axial with second port 191 and third portion 119A ofsecond channel 119 is obtuse or perpendicular relative to fourth portion119B. Fourth portion 119B is formed concurrently with second port 191,in some examples.

Referring generally to FIGS. 1A and 1B and particularly to, e.g., FIGS.2 and 3, conduit 200 for transporting a fluid is disclosed. Conduit 200comprises first collar 102 that comprises channel 118, which iscross-sectionally circumferentially closed. Conduit 200 also comprisesbellows 108 that comprises central axis 180 and first corrugatedoutboard ply 114. Bellows 108 further comprises corrugated inboard ply110, interposed between first corrugated outboard ply 114 and centralaxis 180. Bellows 108 additionally comprises interstitial space 126,interposed between corrugated inboard ply 110 and first corrugatedoutboard ply 114. Bellows 108 also comprises second corrugated outboardply 112 within interstitial space 126. Conduit 200 additionallycomprises first weld 138, hermetically coupling corrugated inboard ply110, first corrugated outboard ply 114, and first collar 102. Conduit200 also comprises weld-through ring 150, located between corrugatedinboard ply 110 and first corrugated outboard ply 114 and coupled tofirst collar 102 by first weld 138. Conduit 200 further comprises sensor116 that is communicatively coupled with interstitial space 126 viachannel 118 of first collar 102. Second corrugated outboard ply 112 isnot hermetically coupled to first collar 102. The preceding subjectmatter of this paragraph characterizes example 40 of the presentdisclosure.

Conduit 200 provides a compliant structure for transmission of fluids,such as cryogenic fuels, that accommodates displacements encounteredduring operation. A configuration of weld-through ring 150 andinterstitial space 126 between corrugated inboard ply 110 and firstcorrugated outboard ply 114 allows sensor 116 to monitor conditionswithin interstitial space 126. In particular, sensor 116 enablesdetection of leaks in corrugated inboard ply 110 by detecting changes inconditions within interstitial space 126. First weld 138 promotes astrong, reliable, and sealed connection between corrugated inboard ply110, first corrugated outboard ply 114, and first collar 102.Weld-through ring 150 ensures communicative coupling betweeninterstitial space 126 and channel 118 of first collar 102, whichestablishes communicative coupling between sensor 116 and interstitialspace 126. Communicatively coupling interstitial space 126 with sensor116 via channel 118 allows fluid or gas that has leaked intointerstitial space 126 through corrugated inboard ply 110 to be detectedat a location, external to first collar 102. Second corrugated outboardply 112 helps to stiffen bellows 108.

Referring generally to FIGS. 11A-11E and particularly to, e.g., FIGS.2-10, method 300 of fabricating conduit 100, 200 is disclosed. Method300 comprises (block 202) simultaneously corrugating first tubularoutboard ply 115, second tubular outboard ply 113, inserted into firsttubular outboard ply 115, and tubular inboard ply 111, inserted intosecond tubular outboard ply 113, to form bellows 108. Bellows 108comprises central axis 180, first corrugated outboard ply 114, secondcorrugated outboard ply 112, corrugated inboard ply 110, and aninterstitial space 126, interposed between corrugated inboard ply 110and first corrugated outboard ply 114. First corrugated outboard ply 114is formed from first tubular outboard ply 115, second corrugatedoutboard ply 112 is formed from second tubular outboard ply 113, andcorrugated inboard ply 110 is formed from tubular inboard ply 111.Method 300 also comprises (block 204) simultaneously trimming firstcorrugated-inboard-ply end 151 of corrugated inboard ply 110 and firstfirst-corrugated-outboard-ply end 174 of first corrugated outboard ply114 to create trimmed first corrugated-inboard-ply end 156 of corrugatedinboard ply 110 and trimmed first first-corrugated-outboard-ply end 172of first corrugated outboard ply 114. Method 300 further comprises(block 206) simultaneously trimming second corrugated-inboard-ply end163 of corrugated inboard ply 110 and secondfirst-corrugated-outboard-ply end 176 of first corrugated outboard ply114 to create trimmed second corrugated-inboard-ply end 170 ofcorrugated inboard ply 110 and trimmed secondfirst-corrugated-outboard-ply end 177 of first corrugated outboard ply114. Method 300 additionally comprises (block 208) locating weld-throughring 150 between corrugated inboard ply 110 and first corrugatedoutboard ply 114 of bellows 108 at trimmed first corrugated-inboard-plyend 156 of corrugated inboard ply 110 and trimmed firstfirst-corrugated-outboard-ply end 172 of first corrugated outboard ply114. Method 300 also comprises (block 210) locating second weld-throughring 157 between corrugated inboard ply 110 and first corrugatedoutboard ply 114 of bellows 108 at trimmed second corrugated-inboard-plyend 170 of corrugated inboard ply 110 and trimmed secondfirst-corrugated-outboard-ply end 177 of first corrugated outboard ply114. Method 300 further comprises (block 212) simultaneously attachingtrimmed first corrugated-inboard-ply end 156, trimmed firstfirst-corrugated-outboard-ply end 172, and weld-through ring 150 tofirst collar 102 with first weld 138. Method 300 additionally comprises(block 214) simultaneously attaching trimmed secondcorrugated-inboard-ply end 170, trimmed secondfirst-corrugated-outboard-ply end 177, and second weld-through ring 157to second collar 103 with second weld 183. Method 300 also comprises(block 216) forming port 188 through weld-through ring 150 along anaxis, parallel with central axis 180 of bellows 108, after attachingweld-through ring 150 to first collar 102 with first weld 138, so thatport 188 is communicatively coupled with interstitial space 126. Method300 additionally comprises (block 218) forming second port 191 throughsecond weld-through ring 157 along a second axis, parallel with centralaxis 180 of bellows 108, after attaching second weld-through ring 157 tosecond collar 103 with second weld 183, so that second port 191 iscommunicatively coupled with interstitial space 126. Method 300additionally comprises (block 220) communicatively coupling sensor 116with interstitial space 126 via port 188. Method 300 also comprises(block 222) communicatively coupling second sensor 117 with interstitialspace 126 via second port 191 and second channel 119 passing throughsecond collar 103. The preceding subject matter of this paragraphcharacterizes example 41 of the present disclosure.

Method 300 facilitates fabrication of conduit 100, 200 in an efficientand simple manner. Conduit 100, 200 provides a compliant structure fortransmission of fluids, such as cryogenic fuels, that accommodatesdisplacements encountered during operation. Simultaneously corrugatingfirst tubular outboard ply 115, second tubular outboard ply 113, andtubular inboard ply 111 to form bellows 108 promotes corrugations 158 incorrugated inboard ply 110, first corrugated outboard ply 114, andsecond corrugated outboard ply 112 of bellows 108 that are complementaryto each other. The ends of the plies being unconstrained relative to thefirst collar and the second collar, helps reduce stress on the plies ofthe bellows, during formation of the corrugations of the bellows, byallowing the plies to be freely slidable relative to each other as thecorrugations are formed. Simultaneously trimming firstcorrugated-inboard-ply end 151 of corrugated inboard ply 110 and firstfirst-corrugated-outboard-ply end 174 of first corrugated outboard ply114 promotes controlled alignment of trimmed firstcorrugated-inboard-ply end 156 of corrugated inboard ply 110 and trimmedfirst first-corrugated-outboard-ply end 174 of first corrugated outboardply 114. Similarly, simultaneously trimming secondcorrugated-inboard-ply end 163 of corrugated inboard ply 110 and secondfirst-corrugated-outboard-ply end 176 of second corrugated outboard ply112 promotes controlled alignment of trimmed secondcorrugated-inboard-ply end 170 of corrugated inboard ply 110 and trimmedsecond first-corrugated-outboard-ply end 176 of first corrugatedoutboard ply 114. Weld-through ring 150 facilitates formation of firstweld 138 while ensuring communicative coupling between interstitialspace 126 and channel 118 of first collar 102, which establishescommunicative coupling between sensor 116 and interstitial space 126.Second weld-through ring 157 facilitates formation of second weld 183while ensuring communicative coupling between interstitial space 126 andsecond channel 119 of second collar 103, which establishes communicativecoupling between second sensor 117 and interstitial space 126. Port 188of weld-through ring 150 facilitates communicative coupling betweeninterstitial space 126 and channel 118 of first collar 102 afterformation of first weld 138. Second port 191 of second weld-through ring157 facilitates communicative coupling between interstitial space 126and second channel 119 of second collar 103 after formation of secondweld 183. Forming port 188 after trimmed first corrugated-inboard-plyend 156, trimmed first first-corrugated-outboard-ply end 172, andweld-through ring 150 are simultaneously attached to first collar 102with first weld 138 allows communicative coupling between interstitialspace 126 and channel 118 of first collar 102 after first weld 138 isformed. Forming second port 191 after trimmed secondcorrugated-inboard-ply end 170, trimmed secondfirst-corrugated-outboard-ply end 177, and second weld-through ring 157are simultaneously attached to second collar 103 with second weld 183allows communicative coupling between interstitial space 126 and secondchannel 119 of second collar 103 after second weld 183 is formedCommunicatively coupling interstitial space 126 with sensor 116 via port188 and channel 118 passing through first collar 102 allows leaks offluid or gas into interstitial space 126 through corrugated inboard ply110 to be detected at a location, external to first collar 102.Communicatively coupling interstitial space 126 with second sensor 117via second port 191 and second channel 119 passing through second collar103 allows leaks of fluid or gas into interstitial space 126 throughcorrugated inboard ply 110 to be detected at a location, external tosecond collar 103.

First weld 138 penetrates into first collar 102 through both ofcorrugated inboard ply 110 and first corrugated outboard ply 114 andthrough weld-through ring 150. Similarly, second weld 183 penetratesinto second collar 103 through both of corrugated inboard ply 110 andfirst corrugated outboard ply 114 and through second weld-through ring157.

After corrugating second tubular outboard ply 113, second corrugatedoutboard ply 112 comprises first second-corrugated-outboard-ply end 153and second second-tubular-outboard-ply end 165, which is axiallyopposite first second-corrugated-outboard-ply end 153.

Referring generally to FIG. 11A and particularly to, e.g., FIGS. 4 and5, according to method 300, second tubular outboard ply 113, in itsentirety, is within first tubular outboard ply 115 when first tubularoutboard ply 115, second tubular outboard ply 113, and tubular inboardply 111 are simultaneously corrugated. The preceding subject matter ofthis paragraph characterizes example 42 of the present disclosure,wherein example 42 also includes the subject matter according to example41, above.

Second tubular outboard ply 113, in its entirety, being within firsttubular outboard ply 115 when first tubular outboard ply 115, secondtubular outboard ply 113, and tubular inboard ply 111 are simultaneouslycorrugated, facilitates an axial offset of firstsecond-corrugated-outboard-ply end 153 of second corrugated outboard ply112 away from trimmed first corrugated-inboard-ply end 156 and trimmedfirst first-corrugated-outboard-ply end 172 and facilitates an axialoffset of second second-corrugated-outboard-ply end 165 of secondcorrugated outboard ply 112 away from trimmed secondcorrugated-inboard-ply end 170 and trimmed secondfirst-corrugated-outboard-ply end 177, which ensures second corrugatedoutboard ply 112 does not obstruct with first weld 138 and second weld183.

Referring generally to FIG. 11A and particularly to, e.g., FIGS. 4 and5, according to method 300, second tubular outboard ply 113 is shorterthan first tubular outboard ply 115 and tubular inboard ply 111. Thepreceding subject matter of this paragraph characterizes example 43 ofthe present disclosure, wherein example 43 also includes the subjectmatter according to example 41 or 42, above.

Second tubular outboard ply 113, being shorter than first tubularoutboard ply 115, facilitates an axial offset of firstsecond-corrugated-outboard-ply end 153 of second corrugated outboard ply112 away from trimmed first corrugated-inboard-ply end 156 and trimmedfirst first-corrugated-outboard-ply end 172 and facilitates an axialoffset of second second-corrugated-outboard-ply end 165 of secondcorrugated outboard ply 112 away from trimmed secondcorrugated-inboard-ply end 170 and trimmed secondfirst-corrugated-outboard-ply end 177, which ensures second corrugatedoutboard ply 112 does not obstruct with first weld 138 and second weld183.

Referring generally to FIG. 11C and particularly to, e.g., FIGS. 2-3 and7-10, method 300 further comprises (block 224) locating tapered spacer148 within interstitial space 126. Tapered spacer 148 is made of apermeable material. The preceding subject matter of this paragraphcharacterizes example 44 of the present disclosure, wherein example 44also includes the subject matter according to any one of examples 41 to43, above.

Tapered spacer 148 helps to maintain spacing between corrugated inboardply 110 and first corrugated outboard ply 114 at a location, adjacentweld-through ring 150. More specifically, tapered spacer 148 helps toprevent corrugated inboard ply 110 from sharply collapsing aroundweld-through ring 150 when conduit 100 is pressurized, which canintroduce stress risers when conduit 100 is pressurized.

Referring generally to FIG. 11C and particularly to, e.g., FIGS. 2-3 and7-10, according to method 300, (block 224) locating tapered spacer 148comprises (block 226) locating tapered spacer 148 coextensively with atleast a portion of first collar 102 along central axis 180 of bellows108. The preceding subject matter of this paragraph characterizesexample 45 of the present disclosure, wherein example 45 also includesthe subject matter according to example 44, above.

Tapered spacer 148, being coextensive with at least a portion of firstcollar 102 along central axis 180 of bellows 108, helps to preventstress risers from forming, in corrugated inboard ply 110 of bellows108, within the bounds of first collar 102.

Referring generally to FIG. 11C and particularly to, e.g., FIGS. 2-3 and7-10, according to method 300, (block 224) locating tapered spacer 148comprises (block 228) abutting tapered spacer 148 against weld-throughring 150. The preceding subject matter of this paragraph characterizesexample 46 of the present disclosure, wherein example 46 also includesthe subject matter according to example 44 or 45, above.

Abutting tapered spacer 148 against weld-through ring 150 helps tomaintain spacing between corrugated inboard ply 110 and first corrugatedoutboard ply 114 at a location, adjacent weld-through ring 150. Morespecifically, abutting tapered spacer 148 against weld-through ring 150helps to prevent corrugated inboard ply 110 from sharply collapsingaround weld-through ring 150 when conduit 100 is pressurized, which canintroduce undesirable stress risers.

Referring generally to FIG. 11C and particularly to, e.g., FIGS. 2-3 and10, method 300 further comprises (block 230) reducing pressure ininterstitial space 126 to below atmospheric pressure after sensor 116 iscommunicatively coupled with interstitial space 126. The precedingsubject matter of this paragraph characterizes example 47 of the presentdisclosure, wherein example 47 also includes the subject matteraccording to any one of examples 41 to 46, above.

Reducing pressure in interstitial space 126 to below atmosphericpressure helps to prevent excessive separation of corrugated inboard ply110 and second corrugated outboard ply 112 when conduit 100 is used inouter space or outside of the Earth's atmosphere. Furthermore, reducingpressure in interstitial space 126 to below atmospheric pressurepromotes a controlled separation of corrugated inboard ply 110 and firstcorrugated outboard ply 114 when conduit 100 is used in outer space oroutside of the Earth's atmosphere. Such a controlled separation helps tokeep corrugated inboard ply 110 and first corrugated outboard ply 114from excessively pressing against each other, which could impede thetransfer of fluid or gas e.g., propellant from reaching channel 118 andsensor 116. Additionally, controlled separation helps to reduce damagee.g., scuffing caused by contact between corrugated inboard ply 110 andfirst corrugated outboard ply 114.

Referring generally to FIG. 11C and particularly to, e.g., FIGS. 2-3 and10, according to method 300, pressure in interstitial space 126 isreduced by (block 232) creating a pressure gradient across vacuum port120, formed in first collar 102 and communicatively coupled withinterstitial space 126. The preceding subject matter of this paragraphcharacterizes example 48 of the present disclosure, wherein example 48also includes the subject matter according to example 47, above.

Vacuum port 120 promotes the reduction of pressure in interstitial space126 when sensor 116 is communicatively coupled to channel 118. In one ormore examples, pump 197 is communicatively coupled to vacuum port 120and selectively operable to create the pressure gradient across vacuumport 120.

Referring generally to FIG. 11C and particularly to, e.g., FIGS. 2 and3, method 300 further comprises (block 234) sealing vacuum port 120 withpinch-off tube 140 after the pressure in interstitial space 126 isreduced. The preceding subject matter of this paragraph characterizesexample 49 of the present disclosure, wherein example 49 also includesthe subject matter according to example 48, above.

Pinch-off tube 140 provides quick and easy sealing of vacuum port 120after pressure is reduced. Pump 197 is communicatively coupled to vacuumport 120 by pinch-off tube 140. In some examples, pinch-off tube 140 hasa sufficient length that is conducive to multiple pressure-reduction andclosing operations.

Referring generally to FIG. 11D and particularly to, e.g., FIGS. 2-3 and7-10, method 300 further comprises (block 246) decreasing a distancebetween corrugated inboard ply 110 and second corrugated outboard ply112 along central axis 180 away from weld-through ring 150. Thepreceding subject matter of this paragraph characterizes example 50 ofthe present disclosure, wherein example 50 also includes the subjectmatter according to any one of examples 41 to 49, above.

Decreasing the distance along central axis 180 away from weld-throughring 150 allows the distance to be smaller away from first collar 102,while allowing the distance to be larger at first collar 102. Allowingthe distance to be smaller away from first collar 102 promotescompliancy of bellows 108 away from first collar 102. In contrast,allowing the distance to be larger at weld-through ring 150 helps toensure interstitial space 126 is open to channel 118.

Referring generally to FIG. 11D and particularly to, e.g., FIGS. 3, 3A,and 7-10, method 300 further comprises (block 248) locating secondtapered spacer 181 within interstitial space 126. Second tapered spacer181 is made from a permeable material. The preceding subject matter ofthis paragraph characterizes example 51 of the present disclosure,wherein example 51 also includes the subject matter according to any oneof examples 41 to 50, above.

Second tapered spacer 181 helps to maintain spacing between corrugatedinboard ply 110 and first corrugated outboard ply 114 at a location,adjacent second weld-through ring 157. More specifically, second taperedspacer 181 helps to prevent corrugated inboard ply 110 from sharplycollapsing around second weld-through ring 157, which can introducestress risers when conduit 100 is pressurized.

Referring generally to FIG. 11D and particularly to, e.g., FIGS. 3 and3A, according to method 300, (block 248) locating second tapered spacer181 within interstitial space 126 comprises (block 250) locating secondtapered spacer 181 coextensively with at least a portion of secondcollar 103 along central axis 180 of bellows 108. The preceding subjectmatter of this paragraph characterizes example 52 of the presentdisclosure, wherein example 52 also includes the subject matteraccording to example 51, above.

Second tapered spacer 181, being coextensive with at least a portion ofsecond collar 103 along central axis 180 of bellows 108, helps toprevent stress risers from forming, in corrugated inboard ply 110 ofbellows 108, within the bounds of first collar 102.

Referring generally to FIG. 11D and particularly to, e.g., FIGS. 3 and3A, according to method 300, (block 248) locating second tapered spacer181 within interstitial space 126 comprises (block 252) abutting secondtapered spacer 181 against second weld-through ring 157. The precedingsubject matter of this paragraph characterizes example 53 of the presentdisclosure, wherein example 53 also includes the subject matteraccording to examples 51 or 52, above.

Abutting second tapered spacer 181 against second weld-through ring 157helps to maintain spacing between corrugated inboard ply 110 and firstcorrugated outboard ply 114 at a location, adjacent second weld-throughring 157. More specifically, abutting second tapered spacer 181 againstsecond weld-through ring 157 helps to prevent corrugated inboard ply 110from sharply collapsing around second weld-through ring 157 when conduit100 is pressurized, which can introduce undesirable stress risers.

Examples of the present disclosure may be described in the context ofaircraft manufacturing and service method 1100 as shown in FIG. 12 andaircraft 1102 as shown in FIG. 13. During pre-production, illustrativemethod 1100 may include specification and design (block 1104) ofaircraft 1102 and material procurement (block 1106). During production,component and subassembly manufacturing (block 1108) and systemintegration (block 1110) of aircraft 1102 may take place. Thereafter,aircraft 1102 may go through certification and delivery (block 1112) tobe placed in service (block 1114). While in service, aircraft 1102 maybe scheduled for routine maintenance and service (block 1116). Routinemaintenance and service may include modification, reconfiguration,refurbishment, etc. of one or more systems of aircraft 1102.

Each of the processes of illustrative method 1100 may be performed orcarried out by a system integrator, a third party, and/or an operator(e.g., a customer). For the purposes of this description, a systemintegrator may include, without limitation, any number of aircraftmanufacturers and major-system subcontractors; a third party mayinclude, without limitation, any number of vendors, subcontractors, andsuppliers; and an operator may be an airline, leasing company, militaryentity, service organization, and so on.

As shown in FIG. 13, aircraft 1102 produced by illustrative method 1100may include airframe 1118 with a plurality of high-level systems 1120and interior 1122. Examples of high-level systems 1120 include one ormore of propulsion system 1124, electrical system 1126, hydraulic system1128, and environmental system 1130. Any number of other systems may beincluded. Although an aerospace example is shown, the principlesdisclosed herein may be applied to other industries, such as theautomotive industry. Accordingly, in addition to aircraft 1102, theprinciples disclosed herein may apply to other vehicles, e.g., landvehicles, marine vehicles, space vehicles, etc.

Apparatus(es) and method(s) shown or described herein may be employedduring any one or more of the stages of the manufacturing and servicemethod 1100. For example, components or subassemblies corresponding tocomponent and subassembly manufacturing (block 1108) may be fabricatedor manufactured in a manner similar to components or subassembliesproduced while aircraft 1102 is in service (block 1114). Also, one ormore examples of the apparatus(es), method(s), or combination thereofmay be utilized during production stages 1108 and 1110, for example, bysubstantially expediting assembly of or reducing the cost of aircraft1102. Similarly, one or more examples of the apparatus or methodrealizations, or a combination thereof, may be utilized, for example andwithout limitation, while aircraft 1102 is in service (block 1114)and/or during maintenance and service (block 1116).

Different examples of the apparatus(es) and method(s) disclosed hereininclude a variety of components, features, and functionalities. Itshould be understood that the various examples of the apparatus(es) andmethod(s) disclosed herein may include any of the components, features,and functionalities of any of the other examples of the apparatus(es)and method(s) disclosed herein in any combination, and all of suchpossibilities are intended to be within the scope of the presentdisclosure.

Many modifications of examples set forth herein will come to mind to oneskilled in the art to which the present disclosure pertains having thebenefit of the teachings presented in the foregoing descriptions and theassociated drawings.

Therefore, it is to be understood that the present disclosure is not tobe limited to the specific examples illustrated and that modificationsand other examples are intended to be included within the scope of theappended claims. Moreover, although the foregoing description and theassociated drawings describe examples of the present disclosure in thecontext of certain illustrative combinations of elements and/orfunctions, it should be appreciated that different combinations ofelements and/or functions may be provided by alternative implementationswithout departing from the scope of the appended claims. Accordingly,parenthetical reference numerals in the appended claims are presentedfor illustrative purposes only and are not intended to limit the scopeof the claimed subject matter to the specific examples provided in thepresent disclosure.

What is claimed is:
 1. A conduit for transporting a fluid, the conduitcomprising: a first collar that comprises a channel, which iscross-sectionally circumferentially closed; a second collar; a bellowsthat comprises: a central axis; a first corrugated outboard ply; acorrugated inboard ply, interposed between the first corrugated outboardply and the central axis; an interstitial space, interposed between thecorrugated inboard ply and the first corrugated outboard ply; and asecond corrugated outboard ply within the interstitial space; a firstweld, hermetically interconnecting the corrugated inboard ply, the firstcorrugated outboard ply, and the first collar; a second weld,hermetically interconnecting the corrugated inboard ply, the firstcorrugated outboard ply, and the second collar; a weld-through ring,located between the corrugated inboard ply and the first corrugatedoutboard ply and coupled to the first collar by the first weld; and asensor that is communicatively coupled with the interstitial space viathe channel of the first collar; and wherein the second corrugatedoutboard ply is not hermetically coupled to the first collar or thesecond collar.
 2. The conduit according to claim 1, further comprising atapered spacer, located within the interstitial space, and wherein thetapered spacer abuts the weld-through ring.
 3. The conduit according toclaim 2, wherein the tapered spacer is tubular and comprises: afull-thickness end, abutting the weld-through ring and having athickness equal to that of the weld-through ring; a reduced-thicknessend, spaced apart from and opposite the full-thickness end and having athickness less than that of the weld-through ring; and an inner surface,facing the central axis and oblique relative to the central axis; andwherein the inner surface tapers radially outwardly relative to thecentral axis in a direction away from the weld-through ring along thecentral axis.
 4. The conduit according to claim 3, wherein: the bellowscomprises a fluid flow channel, at least partially defined by thecorrugated inboard ply; and a portion of the corrugated inboard ply, incontact with the tapered spacer, is configured to geometrically conformto the inner surface of the tapered spacer when the fluid flow channelis pressurized.
 5. The conduit according to claim 2, wherein the taperedspacer is made of a permeable material.
 6. The conduit according toclaim 1, wherein: the weld-through ring comprises a port, passingthrough the weld-through ring; and the port communicatively couples thechannel with the interstitial space.
 7. The conduit according to claim1, wherein: the first collar comprises a first annular pocket; and aportion of the corrugated inboard ply, a portion of the first corrugatedoutboard ply, and a portion of the weld-through ring are located withinthe first annular pocket of the first collar.
 8. The conduit accordingto claim 1, further comprising a sheath that comprises a reinforcementlayer, and wherein the first corrugated outboard ply is interposedbetween the sheath and the central axis.
 9. The conduit according toclaim 8, wherein the sheath is coupled to the first collar and to thesecond collar.
 10. The conduit according to claim 9, wherein the sheathis movable relative to the first collar and relative to the secondcollar.
 11. The conduit according to claim 8, wherein: the sheathfurther comprises a low-friction layer, interposed between thereinforcement layer of the sheath and the first corrugated outboard plyof the bellows; and the low-friction layer of the sheath has a surfaceroughness lower than that of the reinforcement layer of the sheath. 12.The conduit according to claim 1, wherein: the sensor comprises a firstchamber, containing a first reactant, and a second chamber, containing asecond reactant; the second chamber is isolated from the first chamberand is communicatively coupled with the channel of the first collar; andthe first reactant is identical to the second reactant.
 13. A conduitfor transporting a fluid, the conduit comprising: a first collar thatcomprises a channel, which is cross-sectionally circumferentiallyclosed; a bellows that comprises: a central axis; a first corrugatedoutboard ply; a corrugated inboard ply, interposed between the firstcorrugated outboard ply and the central axis; an interstitial space,interposed between the corrugated inboard ply and the first corrugatedoutboard ply; and a second corrugated outboard ply within theinterstitial space; a first weld, hermetically interconnecting thecorrugated inboard ply, the first corrugated outboard ply, and the firstcollar; a weld-through ring, located between the corrugated inboard plyand the first corrugated outboard ply and coupled to the first collar bythe first weld; and a sensor that is communicatively coupled with theinterstitial space via the channel of the first collar; and wherein thesecond corrugated outboard ply is not hermetically coupled to the firstcollar.
 14. The conduit according to claim 2, wherein the tapered spaceris coextensive with at least a portion of the first collar along thecentral axis of the bellows.
 15. The conduit according to claim 3,wherein the inner surface of the tapered spacer has a linear taper. 16.The conduit according to claim 3, wherein the inner surface of thetapered spacer has a non-linear taper.
 17. The conduit according toclaim 3, wherein the inner surface of the tapered spacer tapers to aknife edge.
 18. The conduit according to claim 2, wherein theweld-through ring is interposed between the channel and the taperedspacer.
 19. The conduit according to claim 6, wherein the port isparallel with the central axis of the bellows.
 20. The conduit accordingto claim 1, wherein: the second collar comprises a second channel, whichis cross-sectionally circumferentially closed; and the conduit furthercomprises: a second weld-through ring, located between the corrugatedinboard ply and the first corrugated outboard ply and coupled to thesecond collar by the second weld; and a second sensor that iscommunicatively coupled with the interstitial space via the secondchannel of the second collar.